<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Standards Conformance</title>
<link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
<link rel="home" href="../../index.html" title="Boost.Regex 7.0.1">
<link rel="up" href="../background.html" title="Background Information">
<link rel="prev" href="performance/section_id4148872883.html" title="Testing leftmost-longest searches (platform = linux, compiler = GNU C++ version 6.3.0)">
<link rel="next" href="redist.html" title="Redistributables">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%"><tr>
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td>
<td align="center"><a href="../../../../../../index.html">Home</a></td>
<td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td>
<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
<td align="center"><a href="../../../../../../more/index.htm">More</a></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="performance/section_id4148872883.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../background.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="redist.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_regex.background.standards"></a><a class="link" href="standards.html" title="Standards Conformance">Standards Conformance</a>
</h3></div></div></div>
<h5>
<a name="boost_regex.background.standards.h0"></a>
        <span class="phrase"><a name="boost_regex.background.standards.c"></a></span><a class="link" href="standards.html#boost_regex.background.standards.c">C++</a>
      </h5>
<p>
        Boost.Regex is intended to conform to the <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1836.pdf" target="_top">Technical
        Report on C++ Library Extensions</a>.
      </p>
<h5>
<a name="boost_regex.background.standards.h1"></a>
        <span class="phrase"><a name="boost_regex.background.standards.ecmascript_javascript"></a></span><a class="link" href="standards.html#boost_regex.background.standards.ecmascript_javascript">ECMAScript
        / JavaScript</a>
      </h5>
<p>
        All of the ECMAScript regular expression syntax features are supported, except
        that:
      </p>
<p>
        The escape sequence \u matches any upper case character (the same as [[:upper:]])
        rather than a Unicode escape sequence; use \x{DDDD} for Unicode escape sequences.
      </p>
<h5>
<a name="boost_regex.background.standards.h2"></a>
        <span class="phrase"><a name="boost_regex.background.standards.perl"></a></span><a class="link" href="standards.html#boost_regex.background.standards.perl">Perl</a>
      </h5>
<p>
        Almost all Perl features are supported, except for:
      </p>
<p>
        (?{code}) Not implementable in a compiled strongly typed language.
      </p>
<p>
        (??{code}) Not implementable in a compiled strongly typed language.
      </p>
<p>
        (*VERB) The <a href="http://perldoc.perl.org/perlre.html#Special-Backtracking-Control-Verbs" target="_top">backtracking
        control verbs</a> are not recognised or implemented at this time.
      </p>
<p>
        In addition the following features behave slightly differently from Perl:
      </p>
<p>
        ^ $ \Z These recognise any line termination sequence, and not just \n: see
        the Unicode requirements below.
      </p>
<h5>
<a name="boost_regex.background.standards.h3"></a>
        <span class="phrase"><a name="boost_regex.background.standards.posix"></a></span><a class="link" href="standards.html#boost_regex.background.standards.posix">POSIX</a>
      </h5>
<p>
        All the POSIX basic and extended regular expression features are supported,
        except that:
      </p>
<p>
        No character collating names are recognized except those specified in the
        POSIX standard for the C locale, unless they are explicitly registered with
        the traits class.
      </p>
<p>
        Character equivalence classes ( [[=a=]] etc) are probably buggy except on
        Win32. Implementing this feature requires knowledge of the format of the
        string sort keys produced by the system; if you need this, and the default
        implementation doesn't work on your platform, then you will need to supply
        a custom traits class.
      </p>
<h5>
<a name="boost_regex.background.standards.h4"></a>
        <span class="phrase"><a name="boost_regex.background.standards.unicode"></a></span><a class="link" href="standards.html#boost_regex.background.standards.unicode">Unicode</a>
      </h5>
<p>
        The following comments refer to <a href="http://unicode.org/reports/tr18/" target="_top">Unicode
        Technical Standard #18: Unicode Regular Expressions version 11</a>.
      </p>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                <p>
                  Item
                </p>
              </th>
<th>
                <p>
                  Feature
                </p>
              </th>
<th>
                <p>
                  Support
                </p>
              </th>
</tr></thead>
<tbody>
<tr>
<td>
                <p>
                  1.1
                </p>
              </td>
<td>
                <p>
                  Hex Notation
                </p>
              </td>
<td>
                <p>
                  Yes: use \x{DDDD} to refer to code point UDDDD.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  1.2
                </p>
              </td>
<td>
                <p>
                  Character Properties
                </p>
              </td>
<td>
                <p>
                  All the names listed under the General Category Property are supported.
                  Script names and Other Names are not currently supported.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  1.3
                </p>
              </td>
<td>
                <p>
                  Subtraction and Intersection
                </p>
              </td>
<td>
                <p>
                  Indirectly support by forward-lookahead:
                </p>
                <p>
                  <code class="computeroutput"><span class="special">(?=[[:</span><span class="identifier">X</span><span class="special">:]])[[:</span><span class="identifier">Y</span><span class="special">:]]</span></code>
                </p>
                <p>
                  Gives the intersection of character properties X and Y.
                </p>
                <p>
                  <code class="computeroutput"><span class="special">(?![[:</span><span class="identifier">X</span><span class="special">:]])[[:</span><span class="identifier">Y</span><span class="special">:]]</span></code>
                </p>
                <p>
                  Gives everything in Y that is not in X (subtraction).
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  1.4
                </p>
              </td>
<td>
                <p>
                  Simple Word Boundaries
                </p>
              </td>
<td>
                <p>
                  Conforming: non-spacing marks are included in the set of word characters.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  1.5
                </p>
              </td>
<td>
                <p>
                  Caseless Matching
                </p>
              </td>
<td>
                <p>
                  Supported, note that at this level, case transformations are 1:1,
                  many to many case folding operations are not supported (for example
                  "ß" to "SS").
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  1.6
                </p>
              </td>
<td>
                <p>
                  Line Boundaries
                </p>
              </td>
<td>
                <p>
                  Supported, except that "." matches only one character
                  of "\r\n". Other than that word boundaries match correctly;
                  including not matching in the middle of a "\r\n" sequence.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  1.7
                </p>
              </td>
<td>
                <p>
                  Code Points
                </p>
              </td>
<td>
                <p>
                  Supported: provided you use the u32* algorithms, then UTF-8, UTF-16
                  and UTF-32 are all treated as sequences of 32-bit code points.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  2.1
                </p>
              </td>
<td>
                <p>
                  Canonical Equivalence
                </p>
              </td>
<td>
                <p>
                  Not supported: it is up to the user of the library to convert all
                  text into the same canonical form as the regular expression.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  2.2
                </p>
              </td>
<td>
                <p>
                  Default Grapheme Clusters
                </p>
              </td>
<td>
                <p>
                  Not supported.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  2.3Default Word Boundaries
                </p>
              </td>
<td>
                <p>
                  Not supported.
                </p>
              </td>
<td class="auto-generated"> </td>
</tr>
<tr>
<td>
                <p>
                  2.4
                </p>
              </td>
<td>
                <p>
                  Default Loose Matches
                </p>
              </td>
<td>
                <p>
                  Not Supported.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  2.5
                </p>
              </td>
<td>
                <p>
                  Named Properties
                </p>
              </td>
<td>
                <p>
                  Supported: the expression "[[:name:]]" or \N{name} matches
                  the named character "name".
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  2.6
                </p>
              </td>
<td>
                <p>
                  Wildcard properties
                </p>
              </td>
<td>
                <p>
                  Not Supported.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  3.1
                </p>
              </td>
<td>
                <p>
                  Tailored Punctuation.
                </p>
              </td>
<td>
                <p>
                  Not Supported.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  3.2
                </p>
              </td>
<td>
                <p>
                  Tailored Grapheme Clusters
                </p>
              </td>
<td>
                <p>
                  Not Supported.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  3.3
                </p>
              </td>
<td>
                <p>
                  Tailored Word Boundaries.
                </p>
              </td>
<td>
                <p>
                  Not Supported.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  3.4
                </p>
              </td>
<td>
                <p>
                  Tailored Loose Matches
                </p>
              </td>
<td>
                <p>
                  Partial support: [[=c=]] matches characters with the same primary
                  equivalence class as "c".
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  3.5
                </p>
              </td>
<td>
                <p>
                  Tailored Ranges
                </p>
              </td>
<td>
                <p>
                  Supported: [a-b] matches any character that collates in the range
                  a to b, when the expression is constructed with the collate flag
                  set.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  3.6
                </p>
              </td>
<td>
                <p>
                  Context Matches
                </p>
              </td>
<td>
                <p>
                  Not Supported.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  3.7
                </p>
              </td>
<td>
                <p>
                  Incremental Matches
                </p>
              </td>
<td>
                <p>
                  Supported: pass the flag <code class="computeroutput"><span class="identifier">match_partial</span></code>
                  to the regex algorithms.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  3.8
                </p>
              </td>
<td>
                <p>
                  Unicode Set Sharing
                </p>
              </td>
<td>
                <p>
                  Not Supported.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  3.9
                </p>
              </td>
<td>
                <p>
                  Possible Match Sets
                </p>
              </td>
<td>
                <p>
                  Not supported, however this information is used internally to optimise
                  the matching of regular expressions, and return quickly if no match
                  is possible.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  3.10
                </p>
              </td>
<td>
                <p>
                  Folded Matching
                </p>
              </td>
<td>
                <p>
                  Partial Support: It is possible to achieve a similar effect by
                  using a custom regular expression traits class.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  3.11
                </p>
              </td>
<td>
                <p>
                  Custom Submatch Evaluation
                </p>
              </td>
<td>
                <p>
                  Not Supported.
                </p>
              </td>
</tr>
</tbody>
</table></div>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright © 1998-2013 John Maddock<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
</div></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="performance/section_id4148872883.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../background.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="redist.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
</body>
</html>
